Re: [PATCH 0/7] x86: remove always-defined CONFIG_AS_* options

[Masahiro Yamada]

Hi Jason,

On Mon, Mar 23, 2020 at 3:53 PM Jason A. Donenfeld <Jason@xxxxxxxxx> wrote:
>
> On Mon, Mar 23, 2020 at 12:36 AM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote:
> >
> > Hi Jason,
> >
> > On Mon, Mar 23, 2020 at 1:28 PM Jason A. Donenfeld <Jason@xxxxxxxxx> wrote:
> > >
> > > Hi again,
> > >
> > > I've consolidated your patches and rebased mine on top, and
> > > incorporated your useful binutils comments. The result lives here:
> > >
> > > https://git.zx2c4.com/linux-dev/log/?h=jd/kconfig-assembler-support
> > >
> > > I can submit all of those to the list, if you want, or maybe you can
> > > just pull them out of there, include them in your v2, and put them in
> > > your tree for 5.7? However you want is fine with me.
> >
> >
> > Your series does not work correctly.
> >
> > I will comment why later.
>
> Bummer, okay. Looking forward to learning what's up. Also, if some
> parts of it are useful (like the resorting and organizing of
> arch/x86/crypto/Makefile), feel free to cannibalize it, keeping what's
> useful and discarding what's not.
>


The answer is mostly in my previous reply to Linus:
https://lkml.org/lkml/2020/3/13/27


I think this problem would happen
for CONFIG_AS_CFI and CONFIG_AS_ADX
since the register in instruction code
is machine-bit dependent.

The former is OK wince we are planning to
remove it.

We need to handle -m64 for the latter.
Otherwise, a problem like commit
3a7c733165a4799fa1 would happen.


So, I think we should merge this
https://lore.kernel.org/patchwork/patch/1214332/
then, fix-up CONFIG_AS_ADX on top of it.

(Or, if we do not need to rush,
we can delete CONFIG_AS_ADX entirely after
we bump the binutils version to 2.23)

Thanks.

-- 
Best Regards
Masahiro Yamada